package list;

public class SingleLinkedList implements ILinkedList {
    static class ListNode{
        public int val;
        public ListNode next;
        public ListNode(int val){
            this.val = val;
        }
    }
    private ListNode head;
    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        node.next = head;
        head = node;
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if(head == null){
            head = node;
            return;
        }
        ListNode cur = head;
        while(cur.next != null){
            cur = cur.next;
        }
        cur.next = node;
    }

    @Override
    public void addIndex(int index, int data) {
        int len = size();
        if(index < 0 || index > len){
            System.out.println("位置不合法");
            return;
        }
        if(index == 0){
            addFirst(data);
            return;
        }
        if(index == len){
            addLast(data);
            return;
        }
        ListNode cur = head;
        while(index - 1 != 0){
            cur = cur.next;
            index--;
        }
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while(cur != null){
            if(cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if(head == null){
            return;
        }
        if(head.val == key){
            head = head.next;
            return;
        }
        ListNode cur = findNodeOfKey(key);
        if(cur == null){
            return;
        }
        ListNode del = cur.next;
        cur.next = del.next;
    }
    private ListNode findNodeOfKey(int key){
        ListNode cur = head;
        while(cur.next != null){
            if(cur.next.val == key){
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }

    @Override
    public void removeAllKey(int key) {
        if(head == null){
            return;
        }
        ListNode pre = head;
        ListNode cur = head.next;
        while(cur != null){
            if(cur.val == key){
                pre.next = cur.next;
                cur = cur.next;
            }else{
                pre = cur;
                cur = cur.next;
            }
        }
        if(head.val == key){
            head = head.next;
        }
    }

    @Override
    public int size() {
        int len = 0;
        ListNode cur = head;
        while(cur != null){
            len++;
            cur = cur.next;
        }
        return len;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while(cur != null){
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }

    @Override
    public void clear() {
        ListNode cur = head;
        while(cur != null){
            ListNode curN = cur.next;
            cur.next = null;
            cur = curN;
        }
        head = null;
    }
}
